SSOV Fuel Flow Switching to Cut Parasitic Pump Power
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Solution Overview
Problem
Conventional fuel delivery systems for gas turbine engines require excessive capability beyond operational needs, leading to parasitic power draw and reliance on electromechanical interconnect devices, which are inefficient and costly.
Innovation Solution
A fuel system utilizing a selection and shutoff valve (SSOV) with integrated electrohydraulic control, including a metering valve, electrohydraulic servo valve, and windmill bypass valve, to manage primary and secondary flows efficiently, reducing reliance on electromechanical devices and optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pumps are sized to exceed required capability for much of the operational envelope, then sufficient fuel flow is ensured under all conditions, but parasitic power draw increases significantly
Solution Approach 1:
The pump system transitions from a static, fixed-capability configuration to a dynamic, variable-capability system. The primary pump can be bypassed or throttled via the SSOV and metering valve, allowing the system to adapt pump capacity to actual operational demands, thereby reducing parasitic power draw while ensuring sufficient fuel flow when needed.
Solution Approach 2:
The invention extracts the excess pump capacity from the main fuel delivery path by introducing a bypass line with SSOV and metering valve. This allows the primary pump to be decoupled from the engine fuel supply when full capacity is not needed, separating the excess flow capability from the actual fuel delivery function.
2Ease of operation
If electromechanical interconnect devices and valves are used to perform shutoff and flow selection, then functional control is achieved, but system complexity and cost increase
Solution Approach 1:
The SSOV integrates multiple functions into a single valve device: it acts as both a shutoff valve for the primary pump and a flow selector between primary and secondary pump sources. This merging of functions reduces the total number of separate electromechanical devices needed in the system.
Solution Approach 2:
The SSOV is designed as a multi-functional component that can perform shutoff, flow selection, and pressure control functions depending on its position and configuration. This universal valve replaces what would traditionally require multiple specialized devices, simplifying the overall system architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides precise flow control, minimizes power consumption, and enhances operational efficiency by eliminating unnecessary bypassing and throttling, while ensuring reliable shutoff and mode transitions.
Implementation Method 1
the primary input can be positioned to cause the primary flow to act on the SSOV to bias the SSOV toward the first position
Implementation Method 2
a back pressure line (115) such that a back pressure acts on the SSOV to bias the SSOV toward the second position such that when the back pressure exceeds a primary flow pressure
Data Source
Figure 1
Figure 2
AI summary
A fuel system (100) can include a selection and shutoff valve, SSOV, (101) configured to allow a primary flow having a primary flow pressure (P3) to pass therethrough in a first state such that the primary flow can travel to an output line (103). The SSOV can also be configured to shut off the primary flow in a second state to prevent the primary flow from travelling to the output line. In the second state, the SSOV can be configured to allow a secondary flow from a secondary flow source (105) to pass therethrough such that the secondary flow can travel to the output line (103).